Research On The Vibration Isolation Performance Optimization Of Automotive Powertrain Mount System

The automobile NVH performance is an important indicator to measure the quality of the automobile, which is also the most direct experience to people. The automobile NVH performance is associated with the power device, transmission device, vehicle system and suspension system and other sub module, wherein the engine is main vibration source of the vehicle vibration. Therefore, the study of how to reduce transmission of the engine to the car body vibration system has an important role in lifting the vehicle NVH performance.This paper studies the power assembly device of a certain automobile, and carried out a detailed analysis and optimization research of the mounting system vibration isolation performance. The main research of this paper contain the system vibration isolation theory, the modeling theory of power assembly suspension system, obtaining the parameters of mounting system, establishing simulation model, vibration response analysis, vibration test and the parameter matching optimization.First, this paper focuses on the analysis of single degree of freedom vibration system and its natural frequency distribution based on suspension system vibration theory. Established the rubber mount and six degree freedom mechanical model of the powertrain mounting system, and deduce its dynamic equations.Then, determine the parameters of power assembly and the suspension dynamic characteristic by a real vehicle testing, and establish the engine exciting force parameters. Integrated other subsystem vehicle parameters, thirteen degrees of freedom suspension system simulation model is established based on the six degree of freedom system. Accordingly, the simulation analysis and the real vehicle vibration test has been combined to a comprehensive analysis of the system vibration isolation performance.Finally, according to both mounting system optimization basic principles and the system vibration isolation analysis results, the optimization objective has been set as decoupling of energy and vibration transmissibility minimum, and the NSGA-Ⅱ multi-objective genetic optimization algorithm of optimization methods is employed to stability analysis to ensure the reliability of the optimization results.